On this subject, many of you will have had the opportunity to appreciate in Europe, especially in those countries that usually call Nordic (some call them directly civilized) the lack of extractor hoods in homes. Is it because it’s cold and they don’t want a single calorie to go down the chimney? Is it because they only eat buttered sandwiches?

And on the other hand, the profusion of regulations in Spain that promote the inclusion of chimneys in our buildings is curious. Perhaps it is due to the mild climate, or the trauma that living for many years in unsanitary housing has created or even the undeniable fondness of cooking fried sardines.

Why is this happening? We protest against these regulatory impositions: it is logical that regulations promote air quality, but the point is that an extractor hood is a large hole in the thermal envelope that can lead to large energy losses. If there are CO2, CO, NOX, etc. meters with which the air quality can be objectively demonstrated, we do not see the reason why there are no alternative systems such as recirculation hoods with carbon filters..

Recirculation hood working example with carbon filters

The habitability regulations

Is it necessary to have a kitchen extraction device installed for a home to have a certificate of occupancy ? We refer to the certificate of occupancy of second occupation because currently, for certificates of first occupation there are other regulations that would regulate the extraction of the kitchen (see the CTE section in this same post)

For old buildings and the certificate of occupancy of second occupation

According to annex 2 of (in which the conditions of the homes used and created before 1984 are defined) For homes created before August 11, 1984:

6.5 Have a kitchen equipment installed so that: a) It is formatted as a minimum for a sink and an electric or gas cooking appliance. b) Estigui in a mateixa peça. c) The peça on this condition does not contain the apparent cap of the hygienic equipment d) The peça on this includes a ventilation to the air lliure directly or through a conduit in which it mechanically activated the ventilation. If the conduit is vertical, the ventilation can be activated statically.

Therefore, it follows that it is not necessary to have an extractor hood in the kitchen for the concession of the habitability certificate to homes prior to August 11, 1984. The only one The requirement for these homes is that the kitchen, the kitchen room, have a cooking appliance and have natural ventilation or through a duct.

For new buildings (according to Decree 141/2012)

In this case, the decreto_2012/decretdf” > In its section 3 (habitability requirements demandable in the dwellings) it is very clear. The kitchen must have a connected cooking appliance (we imagine that it is connected to the energy supply, whether it be electricity, gas, etc.) and that takes the fumes up to the cover . So yes, according to this regulation it is necessary.

c) A kitchen team that is formatted, with a minimum, for an aigüera i have a cooking device, i have a specific extraction system mechanics on the kitchen panel connectat that allowed the extraction de bafs i fums fins a la coberta.

The Decree d’Habitatge is prescriptive in invalidating any alternative solution, contrary to the CTE as we will see in the next point (although it proposes design solutions, it clarifies in the preamble that if the health benefits can be guaranteed with other solutions, they must be accepted)

The Technical Building Code

This regulation would affect the homes created since 2006, which was when the CTE.

The CTE in the basic document DB HS, where the requirements that a building must have in terms of health are defined, and specifically in the DB HS3 where the ventilation parameters are established (air renewal flows, etc.) It is said that apart from the health ventilation (the air needed to breathe healthily) is It must have a specific ventilation of the kitchen appliance with a flow rate of 50 l / s.

It literally goes like this:

Kitchens must have an additional specific ventilation system with mechanical extraction for cooking vapors and contaminants. To do this, an extractor must be provided connected to an extraction duct independent of the general ventilation of the home, which cannot be used for the extraction of air from premises of another use. When this conduit is shared by several extractors, each of these must be equipped with an automatic valve that keeps its connection to the conduit open only when it is operating or with any other anti-reversal system.

Chimney heights and clearances according to CTE

It should be remembered that the same creators of the CTE, stressed that the virtues of this new building regulation in Spain, unlike the previous ones, was going to be benefits. That is, instead of saying how buildings have to be resolved constructively, the building regulations would set objective parameters (insulation, air quality, impermeability …) that could be covered by various technical and constructive solutions that would give analogous benefits.

These innovations in the approach of the state building regulations, the CTE, have nothing to do with municipal and regional regulations, which have a much more closed view and are much more focused on the direct prescription of solutions than on the establishment of parameters of performance objectives.

Note therefore this literal quote from part 1 of the Technical Code:

3. To justify that a building meets the basic requirements established in the CTE, the following may be chosen: a) adopt technical solutions based on the DB, whose application in the project, in the execution of the work or in the maintenance and upkeep of the building, is sufficient to prove compliance with the basic requirements related to said DB; or b) alternative solutions , understood as those that totally or partially deviate from the DB. The designer or project manager may, under their responsibility and with the prior consent of the developer, adopt alternative solutions, provided that they justify documentary evidence that the projected building meets the basic requirements of the CTE because its benefits are, at least, equivalent to those that would be obtained. by the application of the DB

So the CTE would admit alternative solutions to the typical hood connected to the building’s chimney.

Official documents with normative interpretations

In the Madrid city council, resolved inquiries are published in the urban planning department, which would logically have a binding character. In the response from the administration it is a question about a 2005 report in which it was clearly stated that if electric plates are used in the cooking appliance, the existence of the chimney required in the PGM Urban Regulations is not necessary.

In this query, part 1 of the CTE is cited, article 5. 3. b) previously mentioned in this post. and reaffirms what has been said in the report, underlining that if the designer assumes under his responsibility, and with the consent of the developer, that the proposed system is at least equivalent to that proposed in the DB HS 3. But the consultation says that in the event that the designer and promoter opt for this solution, logically, the design and dimensioning of all the elements of the system must be documented with documentation (here there is a wide margin where the municipal technician in charge of approving the project can “play”, which is not guarantees in the answer is that a municipal technician understands the supporting documentation that they have to approve)